How to motivate seller to pay underlying mortage

Say the seller has an underlying mortage.

How do I ensure that he continues to pay the underlying mortgage without me putting money into a black hole? What type of language should be put in the sales agreement?

I’ve done some looking around on the forums and haven’t seen anything that addresses this.

Thanks for your help!

What about putting something in the agreement that states you send the payment for the mortgage amount directly to the institution and send the seller anything that’s left from your agreed upon monthly payment amount? If the seller is worried about you not making the payment, he/she can always contact the bank directly to make sure it’s being paid. I have heard stories before about the buyer paying the seller directly only to have the seller use that money for things besides paying the mortgage.